It is proposed to continue to operate and extend the capabilities of the National Resource for the Mass Spectrometric Analysis of Biological Macromolecules. Emphasis will be placed upon the mass spectrometry (MS) of peptides &proteins, for developing proteomic tools for dissecting cellular function, and for developing novel means for studying viral host interactions and the molecular organization of the mammalian brain. The major subdivisions of the Resource activity will be: basic research in MS, collaborative research on challenging biological problems, high-level bioanalytical service, and dissemination of newly developed technologies to the biomedical community. Basic research will involve the development of (1) novel instrumentation for rapid, ultrasensitive tandem MS of peptides &ultra sensitive detection &characterization of phosphopeptides &phosphoproteins, (2) new methods for inducing efficient fragmentation of peptides &small proteins, (3) second generation methods for MS quantitation of proteins, (4) improved methods for studying dynamic protein interactions, (5) improved methods for elucidating the domains structures of proteins, and (6) as test beds for our new technologies, four large-scale applied projects: (i) a comprehensive description of chromosomes, (ii) comprehensive analysis of cellular membranes (iii) study of viral host interactions, and (iv) unraveling the molecular synaptic code in the mammalian brain. Collaborative research will involve definition and study of protein machines &complexes;cell cycle control;cell division dynamics;control of cellular architecture;DNA replication;control of stress in plants;cellular membrane biogenesis;cell-specific molecular dissection of mammalian synapses;signaling in the brain;mechanism of action of neurotransmitters, therapeutic agents &drugs of abuse in the brain;molecular intervention in Alzheimer's disease;autophagy in axonal dystrophy &degeneration;neuropathogenesis of Parkinson's disease;opioid receptor systems in addiction &analgesic response;gene expression &transcription;chromatin biology &epigenetics;telomere organization;analysis of cellular pathways modulated by herpes viruses;molecular analysis of Sindbis alphavirus, hepatitis C, &BVDV infection in host cells, Host interactions of gene products from HIV-1;structure &function of ions channels, comprehensive definition of cellular membranes;lymphocyte differentiation &maintenance;and immunoglobulin-class switching.